From 0edda1d6813b7ac30593b93edea2daeb2c47ef91 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 12 Apr 2019 12:01:59 +0100 Subject: [PATCH] drm/i915: Flush the CSB pointer reset The HW resets it CSB tail pointer on resetting the engine. Most of the time. In case it doesn't (and for system resume) we write the expected value anyway. For extra paranoia, flush the write before we invalidate the cacheline. Signed-off-by: Chris Wilson Cc: Mika Kuoppala Acked-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20190412110159.10495-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_lrc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 3cb788a223ef..4e0a351bfbca 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -1866,6 +1866,7 @@ static void reset_csb_pointers(struct intel_engine_execlists *execlists) */ execlists->csb_head = reset_value; WRITE_ONCE(*execlists->csb_write, reset_value); + wmb(); /* Make sure this is visible to HW (paranoia?) */ invalidate_csb_entries(&execlists->csb_status[0], &execlists->csb_status[reset_value]); -- 2.30.2